sime

Class Endpoint

java.lang.Object

sime.NetworkElement

sime.Endpoint

public class Endpoint
extends NetworkElement

This class implements a simple TCP endpoint that is composed of sender and receiver objects. The actual work is delegated to the sender when send(NetworkElement, Packet) method is called;
to the receiver when handle(NetworkElement, Packet) is called with a segment containing non-zero payload;
or to the sender when handle(NetworkElement, Packet) is called with a segment having the ACK flag set.

Author:

Ivan Marsic

Field Summary

Fields

Modifier and Type	Field and Description
private Link	networkLayerProtocol Communication link adjoining this endpoint.
protected Receiver	receiver Created in the constructor; we assume a universal TCP receiver.
protected Endpoint	remoteEndpoint Remote endpoint that established a TCP connection with this local endpoint.
protected Sender	sender The sender will be created in the constructor based on the supplied type, such as Tahoe, Reno, etc.

Fields inherited from class sime.NetworkElement

lastTimeProcessCalled, name, simulator

Constructor Summary

Constructors

Constructor and Description
Endpoint(Simulator simulator_, java.lang.String name_, Endpoint remoteTCPendpoint_, java.lang.String senderType_, int rcvWindow_) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
int	getLocalRcvWindow() Returns the receive window size for this endpoint (in bytes) by getting it from the local Receiver component.
Link	getNetworkLayerProtocol()
Endpoint	getRemoteTCPendpoint()
Sender	getSender()
void	handle(NetworkElement source_, Packet packet_) Handle the data segments received from the remote endpoint.
void	process(int mode_) Before calling the local Sender, this method calls Simulator.checkExpiredTimers(TimedComponent) to fire the Sender.rtoTimer if it expired.
void	send(NetworkElement source_, Packet newDataPkt_) "Sends" segments by passing them to the network layer protocol object.
void	setLink(Link adjoiningLink_) Configures this endpoint with the adjoining communication link object, the attribute networkLayerProtocol.
(package private) void	setRemoteTCPendpoint(Endpoint remoteTCPendpoint)
void	timerExpired(int timerType_) Callback method to call when a simulated timer expires.

Methods inherited from class sime.NetworkElement

getName, getSimulator

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

networkLayerProtocol

private Link networkLayerProtocol

Communication link adjoining this endpoint. This object provides network-layer services, link-layer services, etc. I'm simply cutting corners because of the lack of time and I don't want this simulator to become too complex.

receiver

protected Receiver receiver

Created in the constructor; we assume a universal TCP receiver.

remoteEndpoint

protected Endpoint remoteEndpoint

Remote endpoint that established a TCP connection with this local endpoint.

sender

protected Sender sender

The sender will be created in the constructor based on the supplied type, such as Tahoe, Reno, etc.

Constructor Detail

Endpoint

public Endpoint(Simulator simulator_,
        java.lang.String name_,
        Endpoint remoteTCPendpoint_,
        java.lang.String senderType_,
        int rcvWindow_)
         throws java.lang.Exception

Constructor.

Parameters:

simulator_ - the runtime environment

name_ - the name given to this endpoint

remoteTCPendpoint_ - the remote endpoint that established a TCP connection with this local endpoint, if any

senderType_ - the TCP version of the Sender contained in this endpoint—one of: "Tahoe", "Reno", or "NewReno")

rcvWindow_ - the size of the receive window for the TCP Receiver contained in this endpoint

Throws:

java.lang.Exception - when an unknown TCP sender type parameter is passed in

Method Detail

getLocalRcvWindow

public int getLocalRcvWindow()

Returns the receive window size for this endpoint (in bytes) by getting it from the local Receiver component.

getNetworkLayerProtocol

public Link getNetworkLayerProtocol()

Returns:

the network layer protocol for this endpoint

getRemoteTCPendpoint

public Endpoint getRemoteTCPendpoint()

Returns:

the remote TCP endpoint that is in a TCP session with this endpoint

getSender

public Sender getSender()

Returns:

the local TCP sender component

handle

public void handle(NetworkElement source_,
          Packet packet_)

Handle the data segments received from the remote endpoint. By default, our in simulator the communication is one-way, meaning the the sending endpoint sends data and the receiving endpoint sends only ACKs (no data). However, this implementation allows for ACKs piggybacked on data segments from the receiving endpoint.

The actual work is delegated to the sender (for segments that carry an acknowledgment) or to the receiver (for segments that carry data), or both.

Specified by:

handle in class NetworkElement

Parameters:

packet_ - an acknowledgment received from the receiver.

source_ - the immediate source network element that passes this packet; which may not be the original source that generated this packet

process

public void process(int mode_)

Before calling the local Sender, this method calls Simulator.checkExpiredTimers(TimedComponent) to fire the Sender.rtoTimer if it expired.

If the received segment contained an ACK, this method will at the end call Simulator.checkExpiredTimers(TimedComponent) to fire the Receiver.delayedACKtimer and have the receiver transmit any cumulative ACKs.

Specified by:

process in class NetworkElement

Parameters:

mode_ - processing mode: the value 1 requests processing of the sender component of this endpoint; the value 2 requests processing of the receiver component of this endpoint

See Also:

Simulator.run(java.nio.ByteBuffer, int)

send

public void send(NetworkElement source_,
        Packet newDataPkt_)

"Sends" segments by passing them to the network layer protocol object. The sending is delegated to the sender object.

Specified by:

send in class NetworkElement

Parameters:

source_ - the source of the message

newDataPkt_ - the new message to send

setLink

public void setLink(Link adjoiningLink_)

Configures this endpoint with the adjoining communication link object, the attribute networkLayerProtocol.

Parameters:

adjoiningLink_ - the adjoining communication link to set

setRemoteTCPendpoint

void setRemoteTCPendpoint(Endpoint remoteTCPendpoint)

Parameters:

remoteTCPendpoint - the remote TCP endpoint to set

timerExpired

public void timerExpired(int timerType_)

Callback method to call when a simulated timer expires.
Currently, the Endpoint does not set any timers.

See Also:

TimedComponent